When users request access to resources, some authentication systems grant or deny the requests based on behavioral profiles of the users. Such behavior profiles indicate conditions under which the users previously requested access to resources. For example, suppose that a user submits a request to access a resource. If an authentication system finds, in making the request, that the user is behaving anomalously with respect to that user's behavioral profile, the authentication system may take remedial steps before granting the user access to the resource.